1. Field of the Invention
The present invention relates to an airbag system designed to protect the occupants of a vehicle during a collision. More specifically, the invention relates to an airbag system including an extensible tether.
2. Description of Related Art
Inflatable airbags are well accepted for use in motor vehicles and have been credited with preventing numerous deaths and injuries. Some statistics estimate that frontal airbags reduce the fatalities in head-on collisions by 25% among drivers using seat belts and by more than 30% among unbelted drivers. Statistics further suggest that with a combination of a seat belt and an airbag, serious chest injuries in frontal collisions can be reduced by 65% and serious head injuries by up to 75%. Airbag use presents clear benefits, and vehicle owners are frequently willing to pay the added expense for airbags.
Furthermore, the inclusion of inflatable safety restraint devices, or airbags, is now a legal requirement for many new vehicles. Airbags are typically installed in the steering wheel and in the instrument panel on the passenger side of a car. In the event of an accident, an accelerometer within the vehicle measures the abnormal deceleration and triggers the ignition of a charge. Expanding gases from the charge fill the airbags, which immediately inflate in front of the driver and passenger to protect them from impact against the windshield or instrument panel.
Airbag apparatuses have been primarily designed for deployment in front of an occupant's torso, between the torso and the instrument panel. Conventional airbags, such as driver's side or passenger's side airbags protect the occupant's upper torso and head from colliding with a windshield or instrument panel. Such conventional airbag modules for frontal occupant protection deploy from the instrument panel or the steering wheel. This location has several disadvantages, including poor protection for out-of-position (OOP) occupants and unaesthetic tear seams on the instrument panel or steering wheel.
Overhead airbags have been produced in an attempt to provide better protection for out-of-position vehicle occupants and to avoid the necessity of installing airbags in the vehicle instrument panel. Unfortunately, known overhead airbags also have a number of disadvantages. For instance, many overhead bags include high-pressure filling tubes that are attached at one end to an inflator and at the opposite end to the cushion. Folding these filling tubes introduces complexity into the manufacturing and assembly process, increasing the cost of these systems. Moreover, the tubes consume large amounts of valuable space when the airbag system is in a stowed position. The tubes also make the installation process difficult or require modifications to a vehicle to enable installation.
Another type of overhead airbag completely detaches from the roof of the vehicle following inflation. This is done to prevent more rapid deceleration of the occupant's head relative to his body, minimizing the danger of neck or back injury. Unfortunately, because the airbag completely separates from the vehicle, it may be difficult to establish, after an accident, that the airbag properly deployed. Furthermore, in such an embodiment, because the airbag completely detaches from the vehicle following inflation, it may be difficult to ensure proper positioning of the airbag, particularly when angular or lateral forces affect the airbag.
Consequently, it would be an advancement in the art to provide an overhead airbag system that does not require lengthy filling tubes and yet remains attached to the vehicle following deployment. It would be a further advancement in the art if such an airbag could extend away from the roof of the vehicle following inflation such that no unnecessary stress is placed on an occupant's neck. Such a device is disclosed and claimed herein.